A copier is known which is provided with an individual verification system based on a camera.
The camera takes the image of a face. A plurality of face images are registered in a database. The system verifies an individual using the image data of the individual and the image data in the database.
The copier is placed at a certain position which is fixed with respect to a window. The angle of view of the camera is fixed.
However, the intensity of light varies. For the camera, sunlight comes from different directions with different intensities. The brightness around the copier is different at 8.00 am, 12.00 pm and 5.00 pm.
At night, an indoor illuminator, instead of the sunlight coming from the window, irradiates the camera. The light of an identification lamp irradiates the copier from the window at night.
For the camera, the light of a light source comes from different directions and different angles indifferent seasons. The brightness of the light source changes with the weather.
The brightness, the contrast ratio and the light reception direction of an installed camera change with the surroundings.
An individual verification apparatus, even when used to take the face image of the same person, is different in face recognition precision in different environments.